A number of different types of radiographic markers have been developed and used to support the radiographic imaging process. For example, markers indicating “L” or “R” may be used to identify left or right areas or sections of the body that appear on the image. Other markers can identify the patient, doctor, or radiologic technician, date, imaging facility, and other information. Markers can also be used to show the orientation of the exposed area. To use a marker, the technician sets up the patient for imaging and places one or more markers in an area of the film or other type of receiver that will receive exposure energy but where the marker does not interfere with the diagnostic image content. Just a few illustrative examples of some types of Left/Right markers are described in U.S. Pat. No. 5,640,438 entitled “Radiographic Film Marker Assembly” to Talluto et al. which shows a clip-on marker device; and in U.S. Pat. No. 4,429,412 entitled “X-ray Film Marker” to Pierce et al. which shows a rotatable wheel for L/R marking.
For many types of X-rays, however, more information than mere Left/Right orientation is needed. In mammography, for example, it may be necessary for the technician to record the angle of exposure used for a particular patient. For chest x-rays, recording the angle of inclination of the patient during exposure can be important for proper imaging and diagnosis. Correspondingly, a number of marker solutions for providing information on patient angle have been proposed. For example, U.S. Pat. No. 2,649,548 entitled “Radiographic Clinometer” to Greenberg shows a device used to cast a shadow onto a radiographic plate for showing an inclination angle. U.S. Pat. No. 5,224,147 entitled “Angle Indicator for X-ray Machine” to Collin et al. shows a device with two beveled “gears” at right angles to each other that cooperate to show an inclination angle setting for use in mammography. U.S. Pat. No. 4,267,641 entitled “Radiographic Film Inclinometer” to Shinozaki et al. describes a device for approximating the inclination angle of the radiographic plate using a number of spheres contained within columns that extend orthogonally with respect to the rotation axis. U.S. Pat. No. 7,092,492 entitled “Universal Radiologic Patient Positioning Marker” to Marn describes a device in the form of a block fabricated with radio-opaque letters and fluid for showing overall image receiver orientation.
While there have been a number of different devices and methods proposed for showing the inclination angle of the patient during exposure, however, these have not been widely adopted for a number of reasons. Some of these devices and methods are relatively complex, such as the device described in the Collin et al. '147 patent, and some may require additional calculation, technician setup, or reading skill in order to obtain the inclination angle information from the film. Others, such as the Greenberg '548 device, can be bulky and cumbersome to use.
Thus, there is a need for a radiographic marker for inclination angle that is relatively easy for the operator or technician to use, can be read from film without requiring additional calculation, and can be readily transported from one imaging receiver or plate to the next.